#!/bin/sh
#
# Purpose {{{
# This script will reboot on Windows system
#   1. Try to get UEFI entry number for Windows.
#   2. Define it as default only for next boot.
#   3. Reboot (default) or poweroff the system.
# …
#
# 2023-08-18
# }}}
# Flags {{{
## Exit on error {{{
set -o errexit
## }}}
## Exit on unset var {{{
### Use "${VARNAME-}" to test a var that may not have been set
set -o nounset
## }}}
## Pipeline command is treated as failed {{{
### Not available in POSIX sh − https://github.com/koalaman/shellcheck/wiki/SC3040
#set -o pipefail
## }}}
## Help with debugging {{{
### Call the script by prefixing it with "TRACE=1 ./script.sh"
if [ "${TRACE-0}" -eq 1 ]; then set -o xtrace; fi
## }}}
# }}}
# Vars {{{
PROGNAME=$(basename "${0}"); readonly PROGNAME
PROGDIR=$(readlink --canonicalize-missing $(dirname "${0}")); readonly PROGDIR
ARGS="${*}"; readonly ARGS
readonly NBARGS="${#}"
[ -z "${DEBUG-}" ] && DEBUG=1
## Export DEBUG for sub-script
export DEBUG

## Default values for some vars
readonly FLAG_REBOOT_DEFAULT="0"
readonly FLAG_POWEROFF_DEFAULT="1"
readonly WINDOWS_BASE_LABEL_DEFAULT="Windows"

## Colors
readonly PURPLE='\033[1;35m'
readonly RED='\033[0;31m'
readonly RESET='\033[0m'
readonly COLOR_DEBUG="${PURPLE}"
# }}}
usage() {                                                       # {{{

	cat <<- HELP
usage: $PROGNAME [-d|-h|-l|-r|-s]

Try to reboot to Windows system.

EXAMPLES :
    - Reboot to Windows system
        ${PROGNAME}

    - Define Windows for next boot but poweroff the system
        ${PROGNAME} --poweroff

    - Search for a specific Windows label
        ${PROGNAME} --label "Windows Boot Manager"

OPTIONS :
    -d,--debug
        Enable debug messages.

    -h,--help
        Print this help message.

    -l,--label,--windows-label
        Define a different label to search for Windows UEFI entry.
        (default: ${WINDOWS_BASE_LABEL_DEFAULT})

    -r,--reboot
        Reboot the system (default behaviour).

    -s,--shutdown,--poweroff,--halt
        Ask to shutdown the system.

    -u,--uefi,--uefi-entry
        Define the UEFI entry to use.
        (default: first matching from efibootmgr + windows-label)

HELP
}
# }}}
debug_message() {                                               # {{{

	local_debug_message="${1}"

	## Print message if DEBUG is enable (=0)
	[ "${DEBUG}" -eq "0" ] && printf '\e[1;35m%-6b\e[m\n' "DEBUG − ${PROGNAME} : ${local_debug_message}"

	unset local_debug_message

	return 0
}
# }}}
error_message() {                                               # {{{

	local_error_message="${1}"
	local_error_code="${2}"

	## Print message
	printf '%b\n' "ERROR − ${PROGNAME} : ${RED}${local_error_message}${RESET}" >&2

	unset local_error_message

	exit "${local_error_code:=66}"
}
# }}}
define_vars() {                                                 # {{{
	debug_message "-- Define vars BEGIN"
	# If flag_reboot wasn't defined (argument) {{{
	if [ -z "${flag_reboot-}" ]; then
		## Use default value
		readonly flag_reboot="${FLAG_REBOOT_DEFAULT}"
	fi
	# }}}
	# If flag_poweroff wasn't defined (argument) {{{
	if [ -z "${flag_poweroff-}" ]; then
		## Use default value
		readonly flag_poweroff="${FLAG_POWEROFF_DEFAULT}"
	fi
	# }}}
	# If windows_base_label wasn't defined (argument) {{{
	if [ -z "${windows_base_label-}" ]; then
		## Use default value
		readonly windows_base_label="${WINDOWS_BASE_LABEL_DEFAULT}"
	fi
	# }}}
	# If windows_uefi_entry wasn't defined (argument) {{{
	if [ -z "${windows_uefi_entry-}" ]; then
		## Try to get the first matching entry with efibootmgr + windows_base_label
		debug_message "||define_vars − \
Try to get Windows UEFI entry with 'efibootmgr' + windows-label (${windows_base_label})."
		windows_uefi_entry=$(efibootmgr | grep --extended-regexp --max-count=1 -- ".*${windows_base_label}.*" | cut --characters=5-8)
	fi
	# }}}
	# If windows_uefi_entry remains empty {{{
	if [ -z "${windows_uefi_entry-}" ]; then
		error_message "windows_uefi_entry seems empty! Verify the windows_base_label used (${windows_base_label}) and your UEFI configuration ('efibootmgr -v')." 11
	elif [ -n "${windows_uefi_entry}" ]; then
		debug_message "||define_vars − \
The ${RED}${windows_uefi_entry}${COLOR_DEBUG} UEFI entry will be used for Windows."
	else
		error_message "I am not supposed to happen!" 12
	fi
	# }}}
	debug_message "-- Define vars END"
}
# }}}

is_command_available() {                                        # {{{

	local_command_available_cmd="${1}"
	debug_prefix="${2:-}"

	## Return False by default
	return_command_available="1"

	if [ "$(command -v ${local_command_available_cmd})" ]; then
		debug_message "${debug_prefix}is_command_available − \
${RED}${local_command_available_cmd}${COLOR_DEBUG} seems present on this host."
		return_command_available="0"
	else
		debug_message "${debug_prefix}is_command_available − \
${RED}${local_command_available_cmd}${COLOR_DEBUG} is not available on this host."
		return_command_available="1"
	fi

	unset local_command_available_cmd
	unset debug_prefix

	return "${return_command_available}"
}
# }}}

main() {                                                        # {{{

	debug_message "--- MAIN BEGIN"

	## If a command is missing {{{
	### Exit with error message
	is_command_available "efibootmgr" "| " \
		|| error_message "No test_me command available. Please install efibootmgr package with your package manager." 01
	## }}}

	## Define all vars
	define_vars

	## If the expected UEFI entry doesn't exists {{{
	if ! sudo efibootmgr | grep --quiet -- "Boot${windows_uefi_entry}"; then
		error_message "The expected UEFI entry (${windows_uefi_entry}) doesn't seem to exist…" 21
	fi
	## }}}

	## Define next boot entry
	sudo efibootmgr --quiet --bootnext "${windows_uefi_entry}"

	## If BootNext entry doesn't match {{{
	if ! sudo efibootmgr | grep --quiet -- "BootNext: ${windows_uefi_entry}"; then
		error_message "The expected UEFI entry (${windows_uefi_entry}) doesn't seem to be the next one (see 'sudo efibootmgr' BootNext entry)." 22
	fi
	## }}}

	printf '%b' "Reboot/shutdown as requested to winbouse partition\\n"
	[ "${flag_reboot}" -eq "0" ] && sudo systemctl reboot
	[ "${flag_poweroff}" -eq "0" ] && sudo systemctl poweroff

	debug_message "--- MAIN END"
}
# }}}

# Manage arguments                                                # {{{
# This code can't be in a function due to argument management

if [ ! "${NBARGS}" -eq "0" ]; then

	manage_arg="0"

	## If the first argument ask for help (h|help|-h|-help|-*h|-*help) {{{
	if printf -- '%s' "${1-}" | grep --quiet --extended-regexp -- "^-*h(elp)?$"; then
		usage
		exit 0
	fi
	## }}}

	## If the first argument is not an option
	if ! printf -- '%s' "${1}" | grep --quiet --extended-regexp -- "^-+";
	then
		## Print help message and exit
		printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
		printf '%b\n' "---"
		usage

		exit 1
	fi

	# Parse all options (start with a "-") one by one
	while printf -- '%s' "${1-}" | grep --quiet --extended-regexp -- "^-+"; do

	case "${1}" in
		-d|--debug )                          ## debug
			DEBUG=0
			debug_message "--- Manage argument BEGIN"
			;;
		-h|--help )                           ## help message (if it's not the first option)
			usage
			exit 0
			;;
		-l|--label|--windows-label )          ## Set windows_base_label var
			## Move to the next argument
			shift
			## Define var
			readonly windows_base_label="${1}"
			;;
		-r|--reboot )                         ## If a reboot was requested (default behaviour)
			flag_reboot="0"
			flag_poweroff="1"
			;;
		-s|--shutdown|--poweroff|--halt )     ## If a poweroff was requested
			flag_reboot="1"
			flag_poweroff="0"
			;;
		-u|--uefi|--uefi-entry )              ## Set windows_uefi_entry var
			## Move to the next argument
			shift
			## Define var
			readonly windows_uefi_entry="${1}"
			;;
		* )                                   ## unknow option
			printf '%b\n' "${RED}Invalid option: ${1}${RESET}"
			printf '%b\n' "---"
			usage
			exit 1
			;;
	esac

	debug_message "| ${RED}${1}${COLOR_DEBUG} option managed."

	## Move to the next argument
	shift
	manage_arg=$((manage_arg+1))

	done

	debug_message "| ${RED}${manage_arg}${COLOR_DEBUG} argument(s) successfully managed."
else
	debug_message "| No arguments/options to manage."
fi

	debug_message "--- Manage argument END"
# }}}

main

exit 255